Rear Twist Beam optimization by cross beam and bush orientation technique to meet performance targets.

Born Electric SUVs generally feature a high center of gravity (CG) with greater rear axle weight. They use sophisticated multi-link suspension, which offers large scope for ride comfort and handling optimization. The development costs and time associated with the process will position the vehicle in a premium segment. Usually, the twist beam (RTB) is used in lower rear axle weight category vehicles due to its simple design and cost effectiveness. This study showcases exploration for implementation of RTB on higher weight category vehicles, which usually uses multi-link suspension. The limitation of the twist beam is to exhibit lateral force compliance oversteer during cornering, due to large moment arm from wheel center to twist beam bush. Lack of lateral stiffness when compared to multi-link suspension causes delayed rear axle yaw response. It also has reduced scope in ride-handling optimization due to its simple structure and kinematics. So, in order to maximize the performance envelope, system level key performance parameters were identified such as lateral force shear center, vertical shear center position, side view swingarm position and length. The parameters such has cross beam position and profile were explored along with bush orientation and stiffness characteristics. Sensitivity studies on the RTB design attributes were performed on multi-body dynamics tool to meet targeted performance metrics. Similarly, multiple bush angle orientation study was carried out to evaluate trade-off between lateral toe and longitudinal wheel center compliance. The combination of unique cross beam profile and bush characteristics, the current platform functional targets were fulfilled.